Does having sex frequently prevent prostate cancer?

4 September marks International Sexual Wellbeing Day, an opportunity to discuss sexuality from a health perspective as well. Among the questions concerning sexual wellbeing, there is one that is of particular interest to men: can frequent ejaculation reduce the risk of prostate cancer? Some studies have observed a link between more frequent ejaculation and a lower risk of developing this cancer. However, a link does not necessarily imply a cause-and-effect relationship. So what do we know today about the role of sexual activity and ejaculation in preventing this cancer?

The main studies on this topic have considered not only sexual intercourse but every instance in which ejaculation occurs, including masturbation and spontaneous nocturnal emissions. One such study, published in JAMA, dates back over twenty years but is still widely cited. Its aim was to investigate whether there was a link between the frequency of ejaculations and the risk of developing prostate cancer. To do this, researchers followed nearly thirty thousand American men, aged between 46 and 81, who, over a period of eight years, completed questionnaires about their habits and whether they had developed cancer. The researchers found that a high frequency of ejaculation (at least 21 times a month) was associated with a reduced risk of the disease.

But is this observation enough to suggest that frequent ejaculation protects against cancer? No. The development of cancer depends, in fact, on numerous factors. Various hypotheses have been put forward in the literature to explain a possible link between sexual activity and the risk of prostate cancer, including increased exposure to male hormones or sexually transmitted infections. However, none of these hypotheses was confirmed by the data from this study. The opposite hypothesis was therefore also considered: that ejaculating more frequently might have a protective effect on the prostate by promoting the elimination of potentially harmful substances.

The figure of 21 ejaculations per month is derived from an association observed in the study cited, not from a threshold proven to be protective. The most recent European guidelines are also clear on this point. They clarify that, compared with a range of 4–7 ejaculations per month, 21 or more ejaculations per month have been associated with an approximately 20 per cent lower risk of developing prostate cancer. However, no cause-and-effect relationship is established.

No: the frequency of sexual intercourse and that of ejaculation are, in fact, distinct concepts with effects that are thought to differ.